/*
 * Copyright 2002-2019 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.http.client.reactive;

import io.netty.buffer.ByteBuf;
import io.netty.handler.codec.http.cookie.DefaultCookie;
import org.reactivestreams.Publisher;
import org.springframework.core.io.buffer.DataBuffer;
import org.springframework.core.io.buffer.DataBufferFactory;
import org.springframework.core.io.buffer.NettyDataBufferFactory;
import org.springframework.http.HttpMethod;
import org.springframework.http.ZeroCopyHttpOutputMessage;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;
import reactor.netty.NettyOutbound;
import reactor.netty.http.client.HttpClientRequest;

import java.net.URI;
import java.nio.file.Path;
import java.util.Collection;

/**
 * {@link ClientHttpRequest} implementation for the Reactor-Netty HTTP client.
 *
 * @author Brian Clozel
 * @see reactor.netty.http.client.HttpClient
 * @since 5.0
 */
class ReactorClientHttpRequest extends AbstractClientHttpRequest implements ZeroCopyHttpOutputMessage {

    private final HttpMethod httpMethod;

    private final URI uri;

    private final HttpClientRequest request;

    private final NettyOutbound outbound;

    private final NettyDataBufferFactory bufferFactory;


    public ReactorClientHttpRequest(HttpMethod method, URI uri, HttpClientRequest request, NettyOutbound outbound) {
        this.httpMethod = method;
        this.uri = uri;
        this.request = request;
        this.outbound = outbound;
        this.bufferFactory = new NettyDataBufferFactory(outbound.alloc());
    }

    private static Publisher<ByteBuf> toByteBufs(Publisher<? extends DataBuffer> dataBuffers) {
        return Flux.from(dataBuffers).map(NettyDataBufferFactory::toByteBuf);
    }

    @Override
    public DataBufferFactory bufferFactory() {
        return this.bufferFactory;
    }

    @Override
    public HttpMethod getMethod() {
        return this.httpMethod;
    }

    @Override
    public URI getURI() {
        return this.uri;
    }

    @Override
    public Mono<Void> writeWith(Publisher<? extends DataBuffer> body) {
        return doCommit(() -> {
            // Send as Mono if possible as an optimization hint to Reactor Netty
            if (body instanceof Mono) {
                Mono<ByteBuf> byteBufMono = Mono.from(body).map(NettyDataBufferFactory::toByteBuf);
                return this.outbound.send(byteBufMono).then();

            }
            else {
                Flux<ByteBuf> byteBufFlux = Flux.from(body).map(NettyDataBufferFactory::toByteBuf);
                return this.outbound.send(byteBufFlux).then();
            }
        });
    }

    @Override
    public Mono<Void> writeAndFlushWith(Publisher<? extends Publisher<? extends DataBuffer>> body) {
        Publisher<Publisher<ByteBuf>> byteBufs = Flux.from(body).map(ReactorClientHttpRequest::toByteBufs);
        return doCommit(() -> this.outbound.sendGroups(byteBufs).then());
    }

    @Override
    public Mono<Void> writeWith(Path file, long position, long count) {
        return doCommit(() -> this.outbound.sendFile(file, position, count).then());
    }

    @Override
    public Mono<Void> setComplete() {
        return doCommit(this.outbound::then);
    }

    @Override
    protected void applyHeaders() {
        getHeaders().forEach((key, value) -> this.request.requestHeaders().set(key, value));
    }

    @Override
    protected void applyCookies() {
        getCookies().values().stream().flatMap(Collection::stream)
                .map(cookie -> new DefaultCookie(cookie.getName(), cookie.getValue()))
                .forEach(this.request::addCookie);
    }

}
